SixSigmaSymbols.xlsx

Alpha, risk of rejecting the null hypothesis erroneously

Average failure rate

Analysis of means

Analysis of variance

Acceptable quality level

Average run length

Beta, risk of not rejecting the null hypothesis erroneously

Control chart for nonconformities

Cause and effect (diagram)

Center line in an SPC chart

Cumulative distribution function

Capability index which shows the process capability potential but does not consider how centered the process is.

Capability index used to compare the natural tolerance of a process within the specification limits. Cpk has a value equal to Cp if the process is centered on the nominal; if Cpk is negative, the process mean is outside of the specification limits; if Cpk is between 0 and 1 then the natural tolerances of the process falls outside the spec limits.

Cost of poor quality

Critical to cost

Critical to delivery

Critical to process

Critical to quality

Control chart which plots the cumulative deviation of each subgroup’s average from the nominal value.

Demerit chart

Degrees of freedom

Design of experiments

Defects per million

Defects per million opportunities

Failure mode and effects analysis

Gage repeatability and reproducibility

Null hypothesis

Alternative hypothesis

Knowledge centered activity

Key process input variables

Key process output variables

Lower control limit (in SPC)

Mu, population true mean

Estimate of population mean

Mean square

Measurement Systems Analysis

Mean time between failures

Sample size

SPC chart of number of nonconforming items

Nominal group technique

probability

Control chart of the proportion of defective units (or fraction defective) in a subgroup. Based on the binomial distribution

The probability of making a Type I error.

Probability density function

Parts per million (defect rate)

Performance index (AIAG l995b) (calculated using "long-term" standard deviation)

Performance index (AIAG 1995b) (calculated using "long-term" standard deviation)

Precision to tolerance ratio

Quality function deployment

Range (in SPC)

Response surface methodology

Rolled Throughput Yield

Number of failures, correlation coefficient

Coefficient of determination

Sigma, population standard deviation

Standard deviation of a sample

Sample standard deviation chart

Statistical process control

Sum of squares

Upper control limit (SPC)

SPC chart of number of nonconformities per unit

SPC chart of means (i.e., x-bar chart)

SPC chart of individual and moving range measurements